Soulja Boy Group

Can anyone recommend a decent software tool to check how responsive web layouts scale down on older tablet screens? I am building a portfolio site and need to see how navigation elements stay smooth without crashing on mobile devices. A developer in a UK tech forum told me to study the interface of Housebets Casino just to see how they optimize complex menus under heavy server load. This technical headache reminds me of the awful service I experienced in Manchester last week. Ordered a new armchair, the delivery guys left the heavy box on the pavement outside and drove away.